Enhanced melt strength ethylene-based copolymers are useful in a variety of applications, such as those requiring film strength during thermoforming or to increase production rates in processing. Fractional melt index linear low density polyethylene (LLDPE) resins (which have a melt index, I2, of less than 1 dg/min) typically have higher melt strength than polyethylene resins of I2≧1 dg/min. Higher melt strength can translate into greater bubble stability during blown film processing allowing for higher line rates. However, the higher molecular weight of the fractional melt index resins can limit the output rate during extrusion due to higher head pressures. In addition, fractional melt index resins are more prone to melt fracture resulting in a film with poor surface quality and reduced rates as a means to minimize/eliminate melt fracture.
The present invention provides a fractional melt index, broad molecular weight distribution polyethylene resin having both high melt strength and bubble stability but the extrusion characteristics of resins having an I2 equal to greater than 1 dg/min.